placoid
/ˈplækɔɪd/
adjective
- Describing a type of scale found on sharks and rays that is small, hard, and tooth-like, with a pointed tip.
- Unlike the smooth scales of most fish, placoid scales are more like tiny teeth.
- The shark's skin feels rough because it is covered in placoid scales.
- Marine biologists study placoid scales to learn more about ancient shark species.